Darwin, C. R.

Darwin-Hooker Letters

On effect of external conditions: Darwin thinks all variability due to changes in conditions of life because there is more variability under unnatural domestic conditions than under nature, and changed conditions affect the reproductive organs. But why one seedling out of thousands presents some new character transcends the wildest powers of conjecture. Not shaken by "saltus" – he had examined all cases of normal structure resembling monstrosities which appear per saltum. Has fought his tendency to attribute too much to natural selection; perhaps he has too much conquered it.